U.S. patent application number 11/541901 was filed with the patent office on 2008-01-17 for hybrid battery module with a voltage balancing unit and its charging and discharging method.
This patent application is currently assigned to COMPAL ELECTRONICS, INC.. Invention is credited to Chen Chia Chang, Chuang Chih Tarng.
Application Number | 20080012529 11/541901 |
Document ID | / |
Family ID | 38948620 |
Filed Date | 2008-01-17 |
United States Patent
Application |
20080012529 |
Kind Code |
A1 |
Chang; Chen Chia ; et
al. |
January 17, 2008 |
Hybrid battery module with a voltage balancing unit and its
charging and discharging method
Abstract
The present invention relates to a hybrid battery module with
voltage balancing unit, which comprises: a first cell set; a first
programmable fuse; a first discharging switch; a first charging
switch; a first analog front end circuit; a first thermister; a
second cell set; a second programmable fuse; a second discharging
switch; a second charging switch; a second analog front end
circuit; a second thermister; a controller; and a voltage balancing
unit; whereby the voltage of the first cell set and the second cell
set can reach a balance state by the voltage balancing unit; and
during the charging process, the first charging switch and the
second charging switch will simultaneously be turned off when it
meets a safety event; and during the discharging process, the first
programmable fuse and the second programmable fuse will
simultaneously be burned off when it meets a critical safety event
so as to prevent cell from being burned; Furthermore, the present
invention also provides a method for charging and discharging a
hybrid battery module with a voltage balancing unit.
Inventors: |
Chang; Chen Chia; (Taipei,
TW) ; Tarng; Chuang Chih; (Taipei, TW) |
Correspondence
Address: |
John G. Chupa;Law Offices of John Chupa & Associates, P.C.
Suite 50, 28535 Orchard Lake Road
Farmington Hills
MI
48334
US
|
Assignee: |
COMPAL ELECTRONICS, INC.
|
Family ID: |
38948620 |
Appl. No.: |
11/541901 |
Filed: |
October 2, 2006 |
Current U.S.
Class: |
320/116 |
Current CPC
Class: |
Y02E 60/10 20130101;
H02J 7/0016 20130101; H01M 10/4207 20130101 |
Class at
Publication: |
320/116 |
International
Class: |
H02J 7/00 20060101
H02J007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 17, 2006 |
TW |
095126058 |
Claims
1. A hybrid battery module with a voltage balancing unit,
comprising: a first cell set; a first programmable fuse, with a
first end coupled to said first cell set; a first discharging
switch, with a source coupled to a second end of said first
programmable fuse; a first charging switch, with a drain coupled to
a drain of said first discharging switch; a first analog front end
circuit, being respectively coupled to a gate of said first
discharging switch and a gate of said first charging switch, for
detecting a voltage or a current of said first cell set in order to
control ON and OFF of said first discharging switch and said first
charging switch; a first thermister, with an end coupled to a
ground, for detecting a temperature of said first cell set; a
second cell set; a second programmable fuse, with a first end
coupled to said second cell set; a second discharging switch, with
a source coupled to a second end of said second programmable fuse;
a second charging switch, with a drain coupled to a drain of said
second discharging switch; a second analog front end circuit,
respectively coupled to a gate of said second discharging switch
and a gate of said second charging switch, for detecting a voltage
or a current of said second cell set in order to control ON and OFF
of said second discharging switch and said second charging switch;
a second thermister, with an end coupled to a ground, for detecting
a temperature of said second cell set; a controller, being
respectively coupled to another end of said first thermister, a
control terminal of said first programmable fuse, another end of
said second thermister, and a control terminal of said second
programmable fuse; and a voltage balancing unit, being respectively
coupled to said controller, said first charging switch, said first
discharging switch, said second charging switch and said second
discharging switch; such that said first cell set and said second
cell set can be discharged by said voltage balancing unit, so as to
reach a goal of voltage balance.
2. The hybrid battery module with a voltage balancing unit of claim
1, wherein said first discharging switch, said first charging
switch, said second discharging switch and said second charging
switch are field effect transistors (FETs).
3. The hybrid battery module with a voltage balancing unit of claim
1, wherein said first analog front end circuit and said second
analog front end circuit are integrated circuits (ICs).
4. The hybrid battery module with a voltage balancing unit of claim
1, further comprising a memory coupled to said controller for
storing a voltage value and a current value detected by said first
analog front end circuit and said second analog front end circuit
and a temperature value detected by said first thermister and said
second thermister.
5. The hybrid battery module with a voltage balancing unit of claim
4, wherein said memory is an electrically erasable programmable
read only memory (EEPROM).
6. The hybrid battery module with voltage balancing unit of claim.
1, further comprising a first safety protection circuit and a
second safety protection circuit, being respectively coupled to a
control terminal of said first programmable fuse and a control
terminal of said second programmable fuse, wherein a voltage
comparator is disposed inside said first safety protection circuit
and said second safety protection circuit, when said voltage in
said first cell set or said second cell set is higher than a
predetermined value, said voltage comparator controls said control
terminals to burn out said first programmable fuse and/or said
second programmable fuse for protecting said first cell set and/or
said second cell set.
7. The hybrid battery module with voltage balancing unit of claim
1, wherein said voltage balancing unit further comprising: a first
current limited resister, one end being coupled to the drain of
said first charging switch and the drain of said first discharging
switch; a first field effect transistor, the source being coupled
to another end of said first current limited resister, and the gate
being coupled to said controller, wherein said first field effect
transistor further comprises a body diode; a second current limited
resister, one end being coupled to the drain of said second
charging switch and the drain of said second discharging switch;
and a second field effect transistor, the source being coupled to
another end of said second current limited resister, and the gate
being coupled to said controller, wherein said second field effect
transistor further comprises a body diode; whereby, said first cell
set can form a path for discharging through said first current
limited resister and said body diode of said first field effect
transistor when said first discharging switch, said first charging
switch, said second discharging switch and said second charging
switch are turned off; while said second cell set can form a path
for discharging through said second current limited resister and
said body diode of said second field effect transistor, so that the
voltage of said first cell set and said second cell set can reach
balance state.
8. The hybrid battery module with a voltage balancing unit of claim
7, further comprising a precharging circuit, wherein its gate is
coupled to said controller, its drain is coupled to said drain of
said first field effect transistor and said second field effect
transistor, respectively, and its source is coupled to said source
of said first charging switch and an output terminal of said
battery module; for providing a small current to said first and
second cell sets and through said body diode of said first field
effect transistor and said second field effect transistor
respectively for precharging.
9. The hybrid battery module with voltage balancing unit of claim
8, wherein said precharging circuit is a field effect transistor
(FET).
10. A method for charging a hybrid battery module with a voltage
balancing unit, wherein said battery module comprises a first cell
set and a second cell set, a first charging switch and a second
charging switch, and a first fuse and a second fuse, and said
charging method comprising: switching said first cell set and said
second cell set into a charging state; respectively turning on said
first charging switch and said second charging switch and charging
said first cell set and said second cell set; determining whether a
voltage in said first cell set or said second cell set is too high,
and if it is, turning off said first charging switch and said
second charging switch simultaneously; determining whether a
charging current in said first cell set or said second cell set is
too high, and if it is, turning off said first charging switch and
said second charging switch simultaneously; determining whether a
charging temperature in said first cell set or said second cell set
is too high, and if it is, turning off said first charging switch
and said second charging switch simultaneously; determining whether
said voltage in said first cell set or said second cell set is
balanced or not; and if it is not balanced, burning out said first
fuse and said second fuse simultaneously; determining whether said
first charging switch or said second charging switch fails to
function, and if it does, burning out said first fuse and said
second fuse simultaneously; determining whether said voltage in
said first cell set or said second cell set exceeds a threshold
voltage, and if it does, burning out said first fuse and said
second fuse simultaneously; determining whether said first cell set
and said second cell set are fully charged, and if they are not
fully charged, continuously charging said first cell set and said
second cell set; and respectively turning off said first charging
switch and said second charging switch.
11. The method for charging the hybrid battery module with a
voltage balancing unit of claim 10, wherein said first charging
switch and said second charging switch are field effect transistors
(FETs), and said first fuse and said second fuse are programmable
fuses.
12. The method for charging the hybrid battery module with a
voltage balancing unit of claim 10, wherein in said step of
determining whether a voltage in said first cell set or said second
cell set is too high, said high voltage is 4.3V.
13. The method for charging the hybrid battery module with a
voltage balancing unit of claim 10, wherein in said step of
determining whether said voltage in said first cell set or said
second cell set exceeds a threshold voltage, said threshold voltage
is 4.4V.
14. A method for discharging a hybrid battery module with a voltage
balancing unit, wherein the battery module comprises a first cell
set and a second cell set, a first discharging switch and a second
discharging switch, and a first fuse and a second fuse, and said
discharging method comprises: switching said first cell set and
said second cell set into a discharging state; respectively turning
on said first discharging switch and said second discharging switch
and discharging said first cell set and said second cell set;
determining whether a voltage in said first cell set or said second
cell set is too low, and if it is, turning off said first
discharging switch and said second discharging switch
simultaneously; determining whether a discharging current in said
first cell set or said second cell set is too high, and if it is,
turning off said first discharging switch and said second
discharging switch simultaneously; determining a discharging
temperature in said first cell set or said second cell set is too
high, and if it is, turning off said first discharging switch and
said second discharging switch simultaneously; and determining
whether said first discharging switch or said second discharging
switch fails to function, and if it does, burning out said first
fuse and said second fuse simultaneously.
15. The method for discharging the hybrid battery module with a
voltage balancing unit of claim 14, wherein said first discharging
switch and said second discharging switch are field effect
transistors (FETs), and said first fuse and said second fuse are
programmable fuses.
16. The method for discharging the hybrid battery module with a
voltage balancing unit of claim 14, wherein in said step of
determining whether a voltage in said first cell set or said second
cell set is too low, said low voltage is 2.5V.
17. A method for balancing the voltage of a hybrid battery module,
wherein the battery module comprises a first cell set and a second
cell set, a first charging switch and a second charging switch, and
a first discharging switch and a second discharging switch, and
said method comprises: (1) said first and second discharging
switches being turned on and said first and second charging
switches being turned off when the cell sets are assembled
completely; (2) determining whether the voltage of one of the cell
in said first cell set is too high, if it is, turning off a second
field effect transistor; (3) determining whether the voltage of one
of the cell in said second cell set is too high, if it is, turning
off a first field effect transistor; (4) determining whether the
discharging current of said first cell set or said second cell set
is too high, if it is, turning off said first discharging switch
and said second discharging switch simultaneously; and (5)
determining whether the difference of the voltage between said
first cell set and said second cell set exceeds a specific voltage,
if it does, backing to the STEP (2) to continue discharging;
otherwise, turning on said first and second charging switches.
18. The method for balancing the voltage of a hybrid battery module
of claim 17, wherein said first charging switch, said second
charging switch, said first discharging switch and said second
discharging switch are field effect transistors (FETs).
19. The method for balancing the voltage of a hybrid battery module
of claim 17, wherein said specific voltage is 20 mV in STEP
(2).
20. The method for balancing the voltage of a hybrid battery module
of claim 17, wherein said first field effect transistor and said
second field effect transistor further comprises a body diode
respectively.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a hybrid battery module
with a voltage balancing unit and its charging and discharging
method; and more particularly to a hybrid battery module can be
discharged by a voltage balancing unit so as to reach the goal of
voltage balance, and no matter the hybrid battery module is in a
charging mode or a discharging mode, once a cell set meets an
abnormal or a critical safety event, the charging switch, the
discharging switch and fuse of the two cell sets will
simultaneously be turned off, so as to prevent the cell sets from
being damaged.
[0003] 2. Description of the Related Art
[0004] Regarding the conventional battery module and its charging
and discharging method, such as a battery module with a plurality
of cell sets disclosed in US patent Publication No. 20050116688 (US
published patent application). The battery module is mainly used to
prevent a single (or specific) cell from being decayed, and each
cell set therein comprises one or more cells. Such hybrid battery
module with voltage balancing unit uses the central processing unit
(CPU) inside the electronic apparatus to determine which cell
should be in the active state based on the number of the
charging/discharging cycles of the cell. Therefore, each cell set
is charged/discharged in a sequenced manner. However, once one of
the cells encounters a problem during the charging/discharging
operation, the forgoing patent is not able to turn off the battery
charging switches simultaneously, which easily damages the battery
module. Additionally, the cell sets of the forgoing patent are
charged and discharged in series, thus its disadvantages are lower
load capacity and longer charging/discharging time.
SUMMARY OF THE INVENTION
[0005] Therefore, it is a primary objective of the present
invention to provide a hybrid battery module with a voltage
balancing unit and its charging and discharging method, in which
more than two cell sets are used, and different types of cell sets
can be selected for adapting to various sizes of the electronic
apparatus, such that more design flexibility is provided.
[0006] Another objective of the present invention is to provide a
hybrid battery module with a voltage balancing unit and its
charging and discharging method, in which the charging/discharging
operations are performed through the control of the
charging/discharging controlling method in parallel, so as to
provide a higher load capacity and a shorter charging time.
[0007] It is yet another objective of the present invention to
provide a hybrid battery module with a voltage balancing unit and
its charging and discharging method, in which the
charging/discharging operations are performed through the control
of the charging/discharging controlling method in parallel, such
that the voltages (potentials) of different types of cell sets can
reach a balanced state, so as to substantially employ the stored
energy.
[0008] It is yet another objective of the present invention to
provide a hybrid battery module with a voltage balancing unit and
its charging and discharging method, in which the hybrid battery
module comprises a voltage balancing unit, and the first cell set
and the second cell set can reach the goal of voltage balance by
way of using the voltage balancing unit, and during the charging
process, the first charging switch and the second charging switch
will simultaneously be turned off when it meets a safety event.
[0009] To achieve the foregoing objectives, the hybrid battery
module with a voltage balancing unit provided by the present
invention comprises: a first cell set; a first programmable fuse
having a first end coupled to the first cell set; a first
discharging switch having a source coupled to a second end of the
first programmable fuse; a first charging switch having a drain
coupled to a drain of the first discharging switch; a first analog
front end circuit coupled to the gates of the first discharging
switch and the first charging switch respectively for detecting the
voltage or the current of the first cell set in order to control
the ON and OFF of the first discharging switch and the first
charging switch; a first thermister having an end coupled to a
ground for detecting the temperature of the first cell set; a
second cell set; a second programmable fuse having a first end
coupled to the second cell set; a second discharging switch having
a source coupled to a second end of the second programmable fuse; a
second charging switch having a drain coupled to a drain of the
second discharging switch; a second analog front end circuit
coupled to the gates of the second discharging switch and the
second charging switch respectively for detecting the voltage or
the current of the second cell set in order to control the ON and
OFF of the second discharging switch and the second charging
switch; a second thermister having an end coupled to a ground for
detecting the temperature of the second cell set; a controller
coupled to another end of the first thermister, a control terminal
of the first programmable fuse, another end of the second
thermister and a control terminal of the second programmable fuse,
respectively; and a voltage balancing unit coupled to the
controller, the first charging switch, the first discharging
switch, the second charging switch and the second discharging
switch, respectively; whereby the first cell set and the second
cell set can be discharged by the voltage balancing unit, so as to
reach the goal of voltage balance.
[0010] To achieve the foregoing objectives, a method for charging a
hybrid battery module with a voltage balancing unit, wherein the
battery module comprises a first cell set and a second cell set, a
first charging switch and a second charging switch, and a first
fuse and a second fuse, and the charging method comprises:
switching the first cell set and the second cell set into a
charging state; respectively turning on the first charging switch
and the second charging switch and charging the first cell set and
the second cell set; determining whether a voltage in the first
cell set or the second cell set is too high, and if it is, turning
off the first charging switch and the second charging switch
simultaneously; determining whether a charging current in the first
cell set or the second cell set is too high, and if it is, turning
off the first charging switch and the second charging switch
simultaneously; determining whether a charging temperature in the
first cell set or the second cell set is too high, and if it is,
turning off the first charging switch and the second charging
switch simultaneously; determining whether the voltage in said
first cell set or the second cell set is balanced or not; and if it
is not balanced, burning out the first fuse and the second fuse
simultaneously; determining whether the first charging switch or
the second charging switch fails to function, and if it does,
burning out the first fuse and the second fuse simultaneously;
determining whether the voltage in the first cell set or the second
cell set exceeds a threshold voltage, and if it does, burning out
the first fuse and the second fuse simultaneously; determining
whether the first cell set and the second cell set are fully
charged, and if they are not fully charged, continuously charging
the first cell set and the second cell set; and respectively
turning off the first charging switch and the second charging
switch.
[0011] To achieve the foregoing objectives, a method for
discharging a hybrid battery module with a voltage balancing unit
of the present invention is provided, wherein the battery module
comprises a first cell set and a second cell set, a first
discharging switch and a second discharging switch, and a first
fuse and a second fuse, and the discharging method comprises the
following steps: switching the first cell set and the second cell
set into a discharging state; respectively turning on the first
discharging switch and the second discharging switch and
discharging the first cell set and the second cell set; determining
whether the voltage in the first cell set or the second cell set is
too low, and if it is, turning off the first discharging switch and
the second discharging switch simultaneously; determining whether
the discharging current in the first cell set or the second cell
set is too high, and if it is, turning off the first discharging
switch and the second discharging switch simultaneously;
determining the discharging temperature in the first cell set or
the second cell set is too high, and if it is, turning off the
first discharging switch and the second discharging switch
simultaneously; and determining whether the first discharging
switch or the second discharging switch fails to function, and if
it does, burning out the first fuse and the second fuse
simultaneously.
[0012] To achieve the foregoing objectives, a method for balancing
the voltage of a hybrid battery module of the present invention is
provided, wherein the battery module comprises a first cell set and
a second cell set, a first charging switch and a second charging
switch, and a first discharging switch and a second discharging
switch, and the discharging method comprises the following steps:
(1) the first and second discharging switches being turned on and
the first and second charging switches being turned off when the
cell sets are assembled completely; (2) determining whether the
voltage of one of the cell in the first cell set is too high, if it
is, turning off the second field effect transistor; (3) determining
whether the voltage of one of the cell in the second cell set is
too high, if it is, turning off the first field effect transistor;
(4) determining whether the discharging current of the first cell
set or the second cell set is too high, if it is, turning off the
first discharging switch and the second discharging switch
simultaneously; and (5) determining whether the difference of the
voltage between the first cell set and the second cell set exceeds
a specific voltage, if it does, backing to the STEP (2) to continue
discharging; otherwise, turning on the first and the second
charging switches.
BRIEF DESCRIPTION DRAWINGS
[0013] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a portion of this specification. The drawings illustrate
embodiments of the invention, and together with the description,
serve to explain the principles of the invention.
[0014] FIG. 1 is a schematic block diagram showing a hybrid battery
module with a voltage balancing unit according to a preferred
embodiment of the present invention.
[0015] FIG. 2 schematically shows a flow chart illustrating a
method for balancing the voltage of a hybrid battery module
according to a preferred embodiment of the present invention.
[0016] FIG. 3 schematically shows a flow chart illustrating a
method for charging the hybrid battery module with a voltage
balancing unit according to a preferred embodiment of the present
invention.
[0017] FIG. 4 schematically shows a flow chart illustrating a
method for discharging a hybrid battery module with a voltage
balancing unit according to a preferred embodiment of the present
invention.
DESCRIPTION PREFERRED EMBODIMENTS
[0018] FIG. 1 is a schematic block diagram showing a hybrid battery
module with a voltage balancing unit according to a preferred
embodiment of the present invention. The hybrid battery module with
a voltage balancing unit of the present invention at least
comprises: a first cell set 10; a first programmable fuse 11; a
first discharging switch 12; a first charging switch 13; a first
analog front end circuit 14; a first thermister 15; a second cell
set 20; a second programmable fuse 21; a second discharging switch
22; a second charging switch 23; a second analog front end circuit
24; a second thermister 25; a controller 30; and a voltage
balancing unit 40.
[0019] Wherein, the first cell set 10 is a chargeable battery pack
that comprises a plurality of cells.
[0020] The first programmable fuse 11 has three terminals, wherein
a first end is coupled to the first cell set 10, a second end is
coupled to a source of the first discharging switch 12, and a
control terminal is coupled to the controller 30. The controller 30
controls the current to flow between the first end--Control
terminal and the second end--control terminal by applying a low
voltage to the control terminal, such that the temperature on the
resistor (not shown in the figure) is increased to burn out the
first programmable fuse 11.
[0021] The first discharging switch 12 includes but not limited to
a field effect transistor (FET), and the source of the first
discharging switch 12 is coupled to the second end of the first
programmable fuse 11.
[0022] The first charging switch 13 includes but not limited to a
field effect transistor (FET), and a drain of the first charging
switch 13 is coupled to a drain of the first discharging switch
12.
[0023] The first analog front end circuit 14 is an integrated
circuit (IC), which coupled to the gates of the first discharging
switch 12 and the first charging switch 13 respectively, and a
built-in detector (not shown in the figure) detects the voltage or
the current of the first cell set 10 in order to control the ON and
OFF of the first discharging switch 12 and the first charging
switch 13.
[0024] One end of the first thermister 15 is coupled to a ground,
and another end of the first thermister 15 is coupled to the
controller 30 for detecting the temperature of the first cell set
10 and transmitting the detected temperature to the controller 30
for further process.
[0025] The second cell set 20 is also a chargeable battery pack
that comprises a plurality of cells.
[0026] The second programmable fuse 21 has three terminals, wherein
a first end is coupled to the second cell set 20, a second end is
coupled to a source of the second discharging switch 22, and a
control terminal is coupled to the controller 30. The controller 30
controls the current to flow between the first end--control
terminal and the second end--control terminal by applying a low
voltage to the control terminal, such that the temperature on the
resistor (not shown in the figure) is increased to burn out the
second programmable fuse 21.
[0027] The second discharging switch 22 includes but not limited to
a field effect transistor (FET), and the source of the second
discharging switch 22 is coupled to the second end of the second
programmable fuse 21.
[0028] The second charging switch 23 includes but not limited to a
field effect transistor (FET), and a drain of the second charging
switch 23 is coupled to a drain of the second discharging switch
22.
[0029] The second analog front end circuit 24 is an integrated
circuit (IC), which coupled to the gates of the second discharging
switch 22 and the second charging switch 23 respectively, and a
built-in detector (not shown in the figure) detects the voltage or
the current of the second cell set 20 in order to control the ON
and OFF of the second discharging switch 22 and the second charging
switch 23.
[0030] One end of the second thermister 25 is coupled to a ground,
and another end of the second thermister 25 is coupled to the
controller 30 for detecting the temperature of the second cell set
20 and transmitting the detected temperature to the controller 30
for further process.
[0031] The controller 30 is respectively coupled to another end of
the first thermister 15, a control terminal of the first
programmable fuse 11, another end of the second thermister 25, and
a control terminal of the second programmable fuse 21 for receiving
the parameters such as the voltage, current and temperature on the
first cell set 10 that are detected by the first analog front end
circuit 14 and the first thermister 15 and receiving the parameters
such as the voltage, current and temperature on the second cell set
20 that are detected by the second analog front end circuit 24 and
the second thermister 25. Thus the controller 30 can send a control
signal to the control terminals of the first programmable fuse 11
and the second programmable fuse 21 to burn out the first and
second programmable fuses 11 and 12. Alternatively, the controller
30 may send a control signal to the first and second analog front
end circuits 14 and 24 to turn off the first discharging switch 12
or the first charging switch 13 and the second discharging switch
22 or the second charging switch 23 at the same time, which further
stops the charging/discharging operation of the first and second
cell sets 10 and 20.
[0032] The voltage balance unit 40 can be formed by disposing a
bidirectional switch and a current limited resister between the
first cell set 10 and second cell set 20, which include a first
current limited resister 41; a first field effect transistor (FET)
42; a second current limited resister 43; and a second field effect
transistor (FET) 44. The voltage balance unit 40 can also be
installed between the first charging/discharging switch 12, 13 and
the second charging/discharging switch 22, 23 and coupled to the
controller 30, the charging switch 13, the first discharging switch
12, the second charging switch 23 and the second discharging switch
22 respectively to enable the discharging of the first cell set 10
and the second cell set 20 by the voltage balance unit 40 to reach
the goal of the voltage balance.
[0033] One end of the first current limited resister 41 is coupled
to the drain of the first charging switch 13 and the drain of the
first discharging switch 12; the source of the first FET 42 is
coupled to the other end of the first current limited resister 41,
and the gate is coupled to the controller 30. The first FET 42
further comprises a body diode 421 to avoid the backward flowing of
the current from the first cell set 10. One end of the second
current limited resister 43 is coupled to the drain of the second
charging switch 23 and the drain of the second discharging switch
22; the source of the second FET 44 is coupled to the other end of
the second current limited resister 43, and the gate is coupled to
the controller 30. The second FET 44 also comprises a body diode
441 to avoid the backward flowing of the current from the second
cell set 20. Whereby, the first cell set 10 can form a path for
discharging through the first current limited resister 41 and the
body diode 421 of the first FET 42 when the first discharging
switch 12, the first charging switch 13, the second discharging
switch 22 and the second charging switch 23 are turned off, while
the second cell set 20 can form a path for discharging through the
second current limited resister 43 and the body diode 441 of the
second FET 44, so that the voltage of the first cell set 10 and the
second cell set 20 can reach balance state.
[0034] When the first cell set 10 and the second cell set are
assembled into a complete pack, it should be placed for a specific
period of time (for example but not limited to a couple of hours to
more than ten hours, depend on the difference of the voltage of the
battery, the values of the current limited resisters 41,43 of the
voltage balance unit 40 and the capacity of the cell sets 10, 20),
the voltage balance unit 40 can automatically balance the voltage
of the first cell set 10 and the second cell set 20, and the
following are the three conditions of the voltage balancing:
[0035] If the difference of the voltage of the first cell set 10
and the second cell set 20 is too huge(for example but not limited
to more than 20 mv), the first and second charging switches 13, 23
will be turned off, and the first and second discharging switches
12, 22 will be turned on, so are the first and second FET 42, 44 in
the voltage balance unit 40, so that the first cell set 10 and the
second cell set 20 will charge and discharge each other and
consequently reach the balance state. If the difference of the
voltage of the first cell set 10 and the second cell set 20 is
small(for example but not limited to less than 20 mv), the first
and second charging switch 13, 23, the first and second discharging
switch 12, 22 and the first and second FET 42, 43 will be turned
on, so that the voltage of the first cell set 10 and the second
cell set 20 will reach balance in a short time. Because the
difference of the voltage is small, the current of the
bidirectional charging and discharging of the cell sets 10, 20 can
be controlled, the cell sets 10, 20 and the switches 12, 22, 13, 23
can also be protected.
[0036] If the voltage of one of the cell of the first cell set 10
is too high, the second FET 44 in the voltage balance unit 40 will
be turned off in order to limit the charging of the second cell set
20 to the first cell set 10, which can be discharged only. Through
the application of the same rule, when the voltage of one of the
cell of the second cell set 20 is too high, the first FET 42 in the
voltage balance unit 40 will be turned off in order to limit the
charging of the first cell set 10 to the second cell set 20, which
can only be discharged. Such condition is to prevent the voltage of
one of the cell being too high, if the cell set is kept charging
when its voltage is relatively low, a safety event may be
caused.
[0037] To solve the three problems mentioned above, the present
invention provides a method for balancing the voltage of a hybrid
battery module, please refer to FIG.2, which schematically shows a
flow chart illustrating a method for balancing the voltage of a
hybrid battery module according to a preferred embodiment of the
present invention; as shown in the figure, the method for balancing
the voltage of a hybrid battery module of this invention includes
the following steps: the first and second discharging switches 12,
22 will be turned on and the first and second charging switches 13,
23 will be turned off when the cell sets are assembled completely
(STEP 1); determining whether the voltage of one of the cell in the
first cell set 10 is too high, if it is, turning off the second FET
44 (STEP 2); determining whether the voltage of one of the cell in
the second cell set 20 is too high, if it is, turning off the first
FET 42 (STEP 3); determining whether the difference of the voltage
between the first cell set 10 and the second cell set 20 exceeds 20
mv, if it does, backing to the STEP 2 to continue discharging;
otherwise, turning on the first and second charging switches 13,
23(STEP 4).
[0038] In addition, the hybrid battery module with voltage
balancing unit of the present invention further comprises a memory
35, which includes but not limited to an electrically erasable
programmable read only memory (EEPROM). The memory 35 is coupled to
the controller 30 and is used to store the voltage and current
values detected by the first and second front end circuits 14 and
24 and the temperature value detected by the first and second
thermisters 15 and 25, and the stored values are further referenced
by the controller 30.
[0039] Moreover, the hybrid battery module with a voltage balancing
unit of the present invention further comprises a first safety
protection circuit 50 and a second safety protection circuit 55
that are respectively coupled to the control terminals of the first
and second programmable fuses 11 and 21. When the voltage in the
first cell set 10 or the second cell set 20 is higher than a
predetermined value, the control terminals are controlled by a
voltage comparator (not shown in the figure) disposed inside the
first and second safety protection circuits 50 and 55 to burn out
the first programmable fuse and/or the second programmable fuse 11
and 21 in order to protect the first cell set 10 and/or the second
cell set 20.
[0040] Furthermore, the hybrid battery module with a voltage
balancing unit of the present invention further includes a
precharging circuit 60. Wherein its gate is coupled to the
controller 30, its drain is coupled to the drain of the first FET
42 and the second FET 44, respectively, and its source is coupled
to the source of the first charging switch 13 and an output
terminal (BATT+) of the battery module; for providing a small
current to the first and second cell sets 10 and 20 through the
body diode 421, 442 of the first FET 42 and the second FET 44,
respectively for precharging. Wherein, the precharging circuit 60
is a field effect transistors (FETs).
[0041] Therefore, with the hybrid battery module with a voltage
balancing unit mentioned above, the first cell set 10 and the
second cell set 20 of the present invention can be discharged
through the voltage balancing unit 40 in advance, then
charges/discharges the cell sets in parallel after the voltage is
balanced, so as to make the first cell set 10 and the second cell
set 20 provide a higher load capacity and a shorter charging time.
Accordingly, the present invention indeed overcomes the drawbacks
of the conventional hybrid battery module.
[0042] In addition, the present invention also provides a method
for charging the hybrid battery module with a voltage balancing
unit. Please refer to FIG. 3 for a flow chart illustrating a method
for charging the hybrid battery module with a voltage balancing
unit according to a preferred embodiment of the present invention.
In the method for charging the hybrid battery module with a voltage
balancing unit of the present invention, the battery module
comprises a first cell set 10 and a second cell set 20, a first
charging switch 13 and a second charging switch 23, and a first
fuse 11 and a second fuse 21, and the charging method comprises the
following steps: switching the first cell set 10 and the second
cell set 20 into a charging state (step S 1); respectively turning
on the first charging switch 13 and the second charging switch 23
and charging the first cell set 10 and the second cell set 20 (step
S2); determining whether the voltage in the first cell set 10 or
the second cell set 20 is too high, and if it is, turning off the
first charging switch 13 and the second charging switch 23
simultaneously (step S3); determining whether the charging current
in the first cell set 10 or the second cell set 20 is too high, and
if it is, turning off the first charging switch 13 and the second
charging switch 23 simultaneously (step S4); determining whether
the charging temperature in the first cell set 10 or the second
cell set 20 is too high, and if it is, turning off the first
charging switch 13 and the second charging switch 23 simultaneously
(step S5); determining whether the voltage in the first cell set 10
or the second cell set 20 is balanced or not; and if it is not
balanced, burning out the first fuse 11 and the second fuse 21
simultaneously (step S6); determining whether the first charging
switch 13 or the second charging switch 23 fails to function, and
if it does, burning out the first fuse 11 and the second fuse 21
simultaneously (step S7); determining whether the voltage in the
first cell set 10 or the second cell set 20 exceeds a threshold
voltage, and if it does, burning out the first fuse 11 and the
second fuse 21 simultaneously (step S8); determining whether the
first cell set 10 and the second cell set 20 are fully charged, and
if they are not fully charged, continuously charging the first cell
set 10 and the second cell set 20 (step S9); and respectively
turning off the first charging switch 13 and the second charging
switch 23 (step S10).
[0043] In step S2, the first and second charging switches 13 and 23
are turned on respectively to charge the first and second cell sets
10 and 20. Wherein, the first and second charging switches 13 and
23 are field effect transistors (FETs).
[0044] In step S3, it is determined whether the voltage in the
first cell set 10 or the second cell set 20 is too high, and if it
is, the first and second charging switches 13 and 23 are turned off
at the same time. Here, the high voltage is 4.3V, that is when the
voltage in the first cell set 10 or the second cell set 20 is
higher than 4.3V, both of the first and second charging switches 13
and 23 are turned off to prevent the structure of the first cell
set 10 or the second cell set 20 from being damaged.
[0045] In step S4, it is determined whether the charging current in
the first cell set 10 or the second cell set 20 is too high, and if
it is, the first and second charging switches 13 and 23 are turned
off at the same time, such that the first cell set 10 or the second
cell set 20 is not burned out.
[0046] In step S5, it is determined whether the charging
temperature in the first cell set 10 or the second cell set 20 is
too high, and if it is, the first and second charging switches 13
and 23 are turned off at the same time, such that the first cell
set 10 or the second cell set 20 is not burned out.
[0047] In step S6, it is determined whether the voltage in the
first cell set 10 or the second cell set 20 is not balanced, and if
it is not balanced, the first and second fuses 11 and 21 are burned
out at the same time to prevent the current generated by the
unbalanced voltage from flowing into the cells that have a lower
voltage, which will otherwise burn out the cell set.
[0048] In step S7, it is determined whether the first charging
switch 13 or the second charging switch 23 fails to function, and
if it does, the first and second fuses 11 and 21 are burned out at
the same time. The states of the first and second charging switches
13 and 23 are respectively recorded by a bit in the memory 35. For
example, the bit is 1 in ON state and 0 in OFF state. Therefore, in
a case where both of the first and second charging switches 13 and
23 are turned off and the state value read by the controller is 0,
some currents are still detected by the controller on the wire,
which indicates the first and second charging switches 13 and 23
fail to function. In such case, the first and second fuse 11 and 21
are burned out at the same time to prevent the first cell set 10 or
the second cell set 20 from being burned out.
[0049] In step S8, it is determined whether the voltage in the
first cell set 10 or the second cell set 20 exceeds the threshold
voltage, if it does, the first and second fuses 11 and 21 are
burned out at the same time, here the threshold voltage is
4.4V.
[0050] Furthermore, the present invention also provides a method
for discharging the hybrid battery module. Please refer to FIG. 4
for a flow chart illustrating a method for discharging the hybrid
battery module with a voltage balancing unit according to a
preferred embodiment of the present invention. In the method for
discharging the hybrid battery module with a voltage balancing unit
of the present invention, the battery module comprises a first cell
set 10 and a second cell set 20, a first discharging switch 12 and
a second discharging switch 22, and a first fuse 11 and a second
fuse 21, and the discharging method comprises the following steps:
switching the first cell set 10 and the second cell set 20 into a
discharging state (step S1); respectively turning on the first
discharging switch 12 and the second discharging switch 22 and
discharging the first cell set 10 and the second cell set 20 (step
S2); determining whether the voltage in the first cell set 10 or
the second cell set 20 is too low, and if it is, turning off the
first discharging switch 12 and the second discharging switch 22
simultaneously (step S3); determining whether the discharging
current in the first cell set 10 or the second cell set 20 is too
high, and if it is, turning off the first discharging switch 12 and
the second discharging switch 22 simultaneously (step S4);
determining whether the discharging temperature in the first cell
set 10 or the second cell set 20 is too high, and if it is, turning
off the first discharging switch 12 and the second discharging
switch 22 simultaneously (step S5); and determining whether the
first discharging switch 12 or the second discharging switch 22
fails to function, and if it does, burning out the first fuse 11
and the second fuse 21 simultaneously (step S6).
[0051] In step S2, the first and second discharging switch 12 and
22 are turned on respectively to discharge the first and second
cell sets 10 and 20. Wherein, the first and second discharging
switch 12 and 22 are field effect transistors (FETs).
[0052] In step S3, it is determined whether the voltage in the
first cell set 10 or the second cell set 20 is too low, and if it
is, the first and second discharging switch 12 and 22 are turned
off at the same time. Here, the low voltage is 2.5V, that is when
the voltage in the first cell set 10 or the second cell set 20 is
lower than 2.5V, both of the first and second discharging switch 12
and 22 are turned off.
[0053] In step S4, it is determined whether the discharging current
in the first cell set 10 or the second cell set 20 is too high, and
if it is, the first and second discharging switch 12 and 22 are
turned off at the same time to prevent the first cell set 10 or the
second cell set 20 from being burned out.
[0054] In step S5, it is determined whether the discharging
temperature in the first cell set 10 or the second cell set 20 is
too high, and if it is, the first and second discharging switch 12
and 22 are turned off at the same time, so as to prevent the first
cell set 10 or the second cell set 20 from being burned out.
[0055] In step S6, it is determined whether the first discharging
switch 12 or the second discharging switch 22 fails to function,
and if it does, the first and second fuses 11 and 21 are burned out
at the same time to prevent the cell sets from being burned out.
The states of the first and second charging switches 13 and 23 are
respectively recorded by a bit in the memory 35. For example, the
bit is 1 in ON state and 0 in OFF state. Therefore, in a case where
both of the first and second charging switches 13 and 23 are turned
off and the state value read by the controller is 0, meanwhile some
currents are still detected by the controller on the wire, which
indicates the first and second charging switches 13 and 23 fail to
function. In such case, the first and second fuse 11 and 21 are
burned out at the same time to prevent the first cell set 10 or the
second cell set 20 from being burned out. Furthermore, the first
and second fuses 11 and 21 are programmable fuses.
[0056] Accordingly, the implementation of the present invention has
the following advantages:
[0057] 1. More than two cell sets are used in the present
invention, and different types of cell sets can be selected for
adapting to various sizes of the electronic apparatus, such that
more design flexibility is provided by the present invention.
[0058] 2. The charging/discharging operations are performed through
the control of the charging/discharging controlling method in
parallel, such that a higher load capacity and a shorter charging
time are provided.
[0059] 3. The charging/discharging operations are performed through
the control of the charging/discharging controlling method in
parallel, such that the voltages (potentials) of different types of
cell sets can reach a balanced state, so as to substantially employ
the stored energy.
[0060] 4. The hybrid battery module comprises a voltage balancing
unit, which can automatically balance the voltages between the cell
sets.
[0061] In addition, in the battery module of the present invention
and its manufacturing, charging and discharging method, regardless
the battery module is in the charging or discharging mode, as long
as one cell set had encountered an abnormal or threshold safety
condition, the charging switches, discharging switches or fuses are
turned off at the same time to prevent the cell sets from being
damaged. Accordingly, the present invention definitely overcomes
the drawbacks of the conventional battery module and its charging
and discharging method.
[0062] In summation of the description above, the object, technical
characteristics and performance of the present invention are novel
and improve over the prior art and thus is duly submitted for the
patent application.
[0063] Although the invention has been described with reference to
a particular embodiment thereof, it will be apparent to one of the
ordinary skills in the art that modifications to the described
embodiment may be made without departing from the spirit of the
invention. Accordingly, the scope of the invention will be defined
by the attached claims not by the above detailed description.
* * * * *